A calix[4] arene ditopic anion receptor molecule containing two cobalticinium moieties capable of coordinating and electrochemically recognising anions has been reported, P. D. Beer, M. G. B. Drew, C. Hazlewood, D. Hesek, J. Hodacova and S. E. Stokes, J. Chem. Soc., Chem. Commun., 1993, 229. Anions recognised include the dicarboxylate anion adipate.